Autopsy of the racehorse: the regulator’s perspective

On Saturday, May 21, 2016, 2 horses died at Pimlico Racecourse (Baltimore, Maryland) in races preceding the running of the Preakness Stakes. Almost immediately after, social media were flooded with calls for an end to horse racing. People for The Ethical Treatment of Animals (PETA) demanded an investigation. Industry leaders scrambled to defend the sport and the stewardship of its athletes. In the words of the late Yogi Berra, it was “déjà vu all over again.”

In North America, from 2008 through 2014, the occurrence of race-related fatalities in Thoroughbred horses remained constant, at ~1.91 per 1,000 starts (https://goo.gl/msWKCH). When compared with the reported occurrence of fatalities elsewhere in the world (0.3–1.2), ¹ North American racing indefensibly stands alone (Bourke JM. Fatalities on racecourses in Victoria: a seven-year study. Proc 10th Int Conf Racing Analysts and Veterinarians; 1994; 265–268; Stockholm, Sweden; Bailey CJ, et al. Risk factors associated with musculoskeletal injuries in Thoroughbred racing. Proc 11th Int Conf Racing Analysts and Veterinarians; 1996; 509–511; Queensland, Australia; MacDonald DM, Toms TS. Survey into the incidence of race track injuries in the Transvall racing district of South Africa. Proc 10th Int Conf Racing Analysts and Veterinarians; 1994; 262–264; Stockholm, Sweden).

In its 2013 report, the Governor-appointed New York Task Force on Racehorse Health and Safety (https://goo.gl/iOV47o) determined that up to 50% of the 24 race-related fatalities at Aqueduct Racetrack (Ozone Park, New York), which occurred within a 3-mo interval, could have been prevented—but they were not.

A number of safety initiatives, including accreditation of racetracks, expansion of prerace examination protocols, mandated autopsies, changes to medication regulations, enhanced drug testing programs, and investigations into the mechanical and physical properties of racing surfaces and the pathophysiology of fractures, have been implemented nationwide. Despite these measures, there was no change in the occurrence of race-related fatalities between 2008 and 2014. Is one to therefore conclude that the occurrence of racing fatalities is inevitable and immutable?

The California Horse Racing Board’s Postmortem Examination Program, instituted in 1990 in partnership with the California Animal Health and Food Safety Laboratory System, has demonstrated that ~90% of racehorses experiencing catastrophic fractures have preexisting bone lesions that correlate with the fatal injury (Sue Stover, pers. comm., June 2011). This is a vital piece of data that undermines the timeworn adage that the horse simply “took a bad step.” The reality is that the “bad step” is the point when the bone failed as a consequence of aggregated bone lesions resulting from cyclic loading. Thus, a racehorse submitted for autopsy signals failure on more than one level. It is not just the obvious musculoskeletal failure, but the more complex and insidious failure of the trainer, exercise rider, groom, attending veterinarian, and/or regulatory veterinarian to recognize, acknowledge, and/or respond appropriately to the horse’s orthopedic health, or lack thereof. In reality, the trainer who declares that the affected horse “never had a pimple on him” or “was the soundest horse in the barn” reveals far more about himself than his horse.

Charged with the safety and integrity of horseracing, what is the responsibility of the regulatory authority when confronted with a racing fatality? Somber statements to the assembled media that reference the unfortunate nature of the event, the high standard of veterinary care afforded the now-deceased horse, the documented safety of the racing surface, and the risk inherent in all athletic competition appease no one, but actually embrace the untenable status quo.

A measurable reduction in racing fatalities is the mandate if horseracing is to remain viable. To understand how this can be achieved, each fatality must undergo objective and thorough investigation. The mortality review is a process that reconciles facts, as established through autopsy and drug testing, with the preinjury perceptions, decisions, and actions of those managing the horse. The goal of the mortality review is to determine if legitimate opportunities for intervention existed, and if so, why were they not implemented?

The duty and expertise of a board-certified veterinary pathologist is to establish factual information critical to the understanding of the horse’s lesions and injury mechanism. Over the last 30 years, the autopsy process applied to racehorse fatalities has evolved. The process of reworking and refining the exam has been of benefit to the pathologist on the diagnostic floor, the Racing Commission, and, most critically, carries greater potential to benefit the care and management of racehorses. Up to the mid-1980s, musculoskeletal fatality cases were rarely submitted for autopsy. To the regulator, these cases were self-evident, and reports stating “fractured right front leg” affirmed the lack of value in submitting cases. In time, specific anatomic descriptions of fractures and soft tissue lesions provided additional clarity on the nature and extent of the catastrophic injury. Case submission was often initiated to secure impartial documentation of the extent of the injury that resulted in the decision to euthanize the horse, particularly when that decision was made on-track in the absence of owner or trainer consent. In the past 2 decades, the “racing autopsy” has been able to provide insight into the health of the horse prior to its fatal injury. For fracture-related fatalities, this includes an examination of the affected limb, and more important, an examination of the “unaffected” contralateral limb. As bone lesions are almost always bilaterally symmetrical, an examination of the “unaffected” limb is substantially more informative about the horse’s prefracture musculoskeletal health, and reveals that that limb is, in fact, far from “unaffected.”

Drug testing of autopsy-acquired blood and urine, by an accredited racing analytical chemistry laboratory, for both banned substances and controlled therapeutic medications, is an important piece of the puzzle. The detection of controlled therapeutic substances, even at nonviolative concentrations, aids in reconciling discrepancies between autopsy findings and clinical observations of the horse preinjury. Therapeutic medications are not inherently so and can be used injudiciously, a practice that can contribute to a clinical presentation inconsistent with the horse’s actual health. The autopsy establishes a factual basis for accountability and an opportunity for vital education. The trainer confronted with a photograph of full-thickness cartilage defects on the parasagittal articular surfaces of the distal aspect of the cannon bone must justify his assertion that the horse never demonstrated signs of lameness. When, and by whom, was the horse’s soundness evaluated? What medications were administered to the horse and could they have obscured the horse’s clinical presentation? Is it possible that a bilateral lameness became the accepted “normal” for that horse?

Autopsy findings initiate substantive discussions about the diagnosis and management of equine orthopedic disease. The findings generate data to adapt racing business models that have the potential to impact equine health. They offer knowledge and a more appropriate skill set for those charged with managing racehorses, and finally, they contribute factually to a range of discussions related to equine health, safety, and welfare.

A racehorse requiring autopsy evidences the failure of an industry, not simply an individual. The magnitude and scope of the failure can be identified through the mortality review process. With that knowledge, meaningful change can be initiated. Absent the autopsy and the documentation it provides, all that remains is rumor, speculation, and the resultant inertia of an entire industry. And with that, how can we expect anything other than déjà vu all over again?